Depicting the RNA Virome of Hematophagous Arthropods from Belgrade, Serbia.

Hematophagous arthropods are important vectors for zoonotic pathogens. To date, a huge number of viruses have been identified in these arthropods, with a considerable proportion of them being human pathogens. However, the viromes of hematophagous arthropods are still largely unresearched. In this study, a number of arthropods were collected from Belgrade, Serbia including mosquitoes, ticks and bedbugs. The viromes of these arthropods were identified and characterized using Illumina MiSeq sequencing. In total, 21 viruses belonging to 11 families were characterized, with 11 of them representing novel species. These results may contribute to our knowledge of RNA viruses in arthropods and the discovery of novel human pathogens.

Insight into diversity of bacteria belonging to the order Rickettsiales in 9 arthropods species collected in Serbia.

Rickettsiales bacteria in arthropods play a significant role in both public health and arthropod ecology. However, the extensive genetic diversity of Rickettsiales endosymbionts of arthropods is still to be discovered. In 2016, 515 arthropods belonging to 9 species of four classes (Insecta, Chilopoda, Diplopoda and Arachnida) were collected in Serbia. The presence and genetic diversity of Rickettsiales bacteria were evaluated by characterizing the 16S rRNA (rrs), citrate synthase (gltA) and heat shock protein (groEL) genes. The presence of various Rickettsiales bacteria was identified in the majority of tested arthropod species. The results revealed co-circulation of five recognized Rickettsiales species including Rickettsia, Ehrlichia and Wolbachia, as well as four tentative novel species, including one tentative novel genus named Neowolbachia. These results suggest the remarkable genetic diversity of Rickettsiales bacteria in certain arthropod species in this region. Furthermore, the high prevalence of spotted fever group Rickettsia in Ixodes ricinus ticks highlights the potential public health risk of human Rickettsia infection.

[The role of oxidative stress in the pathogenesis of pulmonary emphysema].

OXIDATIVE PULMONARY DAMAGE: The pathogenesis of pulmonary emphysema is incompletely understood. Nearly 90% of all patients with chronic obstructive pulmonary diseases are smokers. Cigarette smoke is a rich source of oxidants. Oxidative stress increases oxidant generation, which cannot be neutralized with antioxidant defense mechanisms. Lipids, proteins and deoxyribonucleic acid are components of the cell that are most sensitive to oxidative damage. Oxygen radicals can modify amino acid side chains, form protein aggregates, cleave peptide bonds, and make proteins more susceptible to proteolytic degradation. It has been shown that neutrophils have a principal effector role in pulmonary tissue damage. Neutrophil elastase can damage air spaces by degrading elastin, and a variety of extracellular membrane proteins, proteoglycans, and glycoproteins. Neutrophil elastase can also stimulate inflammation by increasing interleukin-8 synthesis. Additionally, neutrophil elastase can activate or inactivate inhibitors of neutrophil collagenase, and secretory leukoprotease proteinase inhibitor. Apart from neutrophils, oxidative stress causes activation of other phagocytes and severe inflammatory response ensues. LIPID PEROXILATION AND PULMONARY EMPHYSEMA: Except protein oxidation and lipid peroxidation, oxidants may disturb signal transmission in the cells, as well as normal cell membrane function and function of organelles. Modified structure of deoxyribonucleic acid may cause mutations, which in absence of repairation enzyme activity lead to cell injury. IRON AND OXIDATIVE STRESS: Iron metabolism is also important in the development of pulmonary emphysema due to its role in production of some oxidants.